REVIEWS - LETTERS - REPORTS SAFETY PROBLEMS AND FAULT DETECTION IN PROCESS INDUSTRY

The present article integrates the demands for safe processing and fault detection techniques. The flrst part deals with safety of (chemical) process industry in general. Three main hazardous events with their causes and consequences are shortly described. The section points out the idea that safety analysis should predict parts of the process where early fault detection is indespensible. This is important to have the proper sensors installed. Early fault detection can improve the quality of production and increase the occupational and environmental safety through detecting the faults before they develop to a failure that might cause an accident with all its consequences such as material detriment, environmental damage or lose of human life. The second part brie∞y describes some analytical model-based fault detection techniques. K e y w o r d s: process safety, fault detection, fault isolation, parameter estimation, state observers An expansion of new scientiflc discoveries, technical solutions, automation of technological processes and robotics makes the human population dependent on some machines that can be our friends or/and mortal enemies if not designed, handled and maintained properly. This is also the case where desired global competitiveness cannot be achieved. The global competitiveness depends to a large extent on the efiectiveness of the use of factory automation. The early 1980s heralded the creation of the \Factory of the future". The prevalent image then was a \lights ofi" factory heavily populated by robots, with a few human supervisors keeping track of operations by watching monitors in a central control room. In many cases, this image was not fulfllled. In few words, workers (and wider environment, living and non-living) are still exposed to harmful efiects of the working area and accidents, caused either by process malfunction or incompetence of their colleague workers. Some studies [1] have shown that main causes of the accidents related to automation or control were poor instrumentation (19%) and operator error (19%). Most of the human errors are usually made during start-up operation of the process. The following conclusion can be taken out from the previous discussion: If the degree of automation were higher, the consequences of a human error might be smaller. In addition the co-operation between automation and human operator, it is important to avoid human errors during operation. The occurrence of equipment faults as causes of accidents brings up the requirement that potential failures both in measurement and control equipment, and in process equipment, should be studied. The process design should be prepared for them, thus an equipment failure of the system should not lead to the accident. One of the possible solutions is early detection of malfunctions, called Fault Detection and Isolation (FDI).